Food conditioning chest

ABSTRACT

A food conditioning chest has a generally rectangular tub supported in the housing to define an upwardly opening food well for supporting foodstuffs. Louvered openings are formed in opposite end walls and the front wall and the rear wall of the tub. A return duct communicates with the food well through the openings formed in the end walls and transports return air to an intake chamber formed beneath the tub floor. An intake duct extends from the intake chamber and communicates with the food well through the openings formed in the front wall and the rear wall. A centrifugal fan positioned in the intake chamber circulates air from the return duct and the intake duct. As the air flows through the intake chamber, it passes over at least one heating element which heats the air to a desired temperature.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a food conditioning chest for storingfoodstuffs and, in particular, to a food conditioning chest in whichtempered air is circulated to preserve the foodstuffs.

2. Background Art

Food chests are conventionally used in the food services industry,wherein it is desired to preserve a large quantity of stored food over arelatively long period of time. Commonly, food chests are used ininstitutional environments, such as in schools or hospitals, in whichmany servings of food are stored in a food chest and are periodicallydispensed for consumption by an individual. Often servings arecontinuously dispensed from a food chest as in a `cafeteria line`-typeusage.

Because of the large number of servings often stored within a foodchest, the process of dispensing the servings can become quiteprotracted, and some servings may be stored in the chest for arelatively long time before they are ultimately dispensed. In order toadequately preserve the food, it is therefore important that food chestshave some capability of maintaining food stored therein in a propercondition. Normally food servings must either be kept refrigerated,requiring that heat energy be drawn from the interior of the food chest,or the food servings must be continuously warmed, requiring that heat besupplied to the interior of the food chest.

One approach to conditioning food contained within a food chest has beento circulate conditioned air about the food. Air is drawn from openingsin the chest and then appropriately conditioned, as by heating orcooling the air. Conditioned air is then forced back into the food chestto transfer thermal energy between the interior of the chest and the airto thereby condition the food. The efficiency with which the food isconditioned is directly related to the amount and the condition of airwhich is circulated within the food chest.

One proposed air circulating system is shown in U.S. Pat. No. 3,962,962to Anderson. Anderson discloses a hot cabinet server in whichpre-packaged foods are stored in a rectangular bin. The bin has oppositeupright side walls having vent openings to allow air to flow into andout of the bin, with both inlet vents and outlet vents provided on thesame side of the bin. A common fan draws air from the bin through theoutlet vents and attempts to force air into the bin through the adjacentinlet vents, such that the proximate, opposed flows impede aircirculation and limit the efficiency with which conditioned air can besupplied to the foods contained in the bin. More specifically, cool airis drawn upwardly out of the bin and tends to redirect the incoming,heated air such that heat is prevented from efficiently reaching thefood at the bottom of the bin. In one form of the known air circulatingsystem, air is drawn through only a single return side of the bin,further limiting air circulation.

In addition to the reduced volume of air which is circulated with theknown device, because the pre-conditioned `return` flow and theconditioned `intake` flow are routed closely together, thermal lossesfurther impede the efficiency of the food conditioning. On the sides ofthe bin having both inlet and outlet vents, pre-conditioned return airis drawn from the bin and travels in a path adjacent the conditionedintake air moving toward the inlet vents. Heat is conducted between thereturn and the intake flows and the efficiency of the food conditioningprocess is reduced.

Another problem with the Anderson structure occurs at startup. Theunheated return air is drawn against the heater so as to effect coolingthereof. This lengthens the startup time for the device.

SUMMARY OF THE INVENTION

The present invention comprehends an improved food conditioning chestadapted for preserving foodstuffs contained within the chest by theefficient circulation of conditioned air about the foodstuffs.

In the exemplary embodiment of the invention, a food conditioning chesthas an outer housing having an open top and a generally rectangular tubsupported in the housing. The tub has a front wall and a rear wallspaced apart by opposite end walls and connected by a tub floor todefine an upwardly opening food well for supporting foodstuffs withinthe food conditioning chest.

Louvered openings are formed in each of the opposite end walls and thefront wall and the rear wall. A return duct communicates with the foodwell through the openings formed in the end walls. The return duct ispositioned outside the food well and extends downwardly along each ofthe end walls and beneath the tub floor. An intake duct communicateswith the food well through the openings formed in the front wall and therear wall and extends downwardly along the outside of the tub to anintake chamber formed beneath the tub floor.

A centrifugal fan draws air from the food well through the openingsformed in the end walls of the tub and through the return duct into theintake chamber. As the air flows through the intake chamber, it passesover a number of heating elements which heat the air to a desiredtemperature. Flow diverters positioned in the intake chamber direct theheated air toward the intake duct for delivery to the food well.Operation of the fan draws the heated air through the intake duct andinto the food well through the openings formed in the front wall and theend wall.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will be apparent from thefollowing detailed description taken in connection with the accompanyingdrawings wherein:

FIG. 1 is a fragmentary perspective view of a food conditioning chestaccording to the present invention;

FIG. 2 is a front elevation view of the food conditioning chestillustrated in FIG. 1;

FIG. 3 is a plan view of the food conditioning chest illustrated in FIG.1; and

FIG. 4 is an end elevation view of the food conditioning chestillustrated in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

In the illustrative embodiment of the invention disclosed in thedrawings, a food conditioning chest generally designated 10 is shown tocomprise an outer housing 12 having generally upright wall panels 14 and16 formed of metal, wood or another known material suitable for thepurposes described hereinbelow. Although not shown in the broken outview of FIG. 1, housing 12 has four successively connected wall panelsdefining a substantially rectangular open top 18.

A stepped railing 20 is supported by the upper edges of the housing wallpanels 14 and 16 and extends completely around the periphery of the opentop 18. Stepped railing 20 has a number of vertically spacedsubstantially horizontal steps 22 and 24 projecting inwardly of thehousing wall panels 14 and 16 for slidably supporting covers (not shown)which selectively seal the open top 18 of the food chest 10 and permitaccess thereto. It should be understood that while the preferredembodiment shows a top access to the chest 10, the invention alsocomprehends access elsewhere through the housing 12.

The railing 20 cascades downwardly into the interior of the housing 12and terminates in a substantially horizontal out-turned flange 26. Asshown in FIG. 1, the out-turned flange 26 of the stepped railing 20mounts an upwardly opening, generally rectangular tub 28 dependingwithin the housing 12. The tub communicates with the open top 18 ofhousing 12 and defines a food well 30 for storing foodstuffs to bepreserved within the food chest 10, as will be described below.

Referring also to FIGS. 2 and 3, rectangular tub 28 has an upright frontwall 32 spaced apart from a substantially parallel rear wall 34 by apair of opposite end walls 36 and 38. A generally horizontal tub floor40 interconnects the bottom edges of front wall 32, rear wall 34 and endwalls 36 and 38 and is adapted to support foodstuffs within the foodwell 30.

A generally U-shaped return duct 42 extends downwardly along the outersides of opposite end walls 36 and 38 and across the bottom side of tubfloor 40. Return duct 42 is supported beneath the tub floor 40 by meansof a subfloor panel 44 connected to the bottom edges of tub walls 32,34, 36 and 38 which extend downwardly beyond the tub floor 40. Returnduct 42 communicates with the interior of the food well 30 through aplurality of downwardly angled louvers 46 formed in the end walls 36 and38 approximately midway between the front wall 32 and the rear wall 34.As will be shown, return duct 42 is thereby effective to transport airaway from the food well 30 for subsequent conditioning.

As best shown in FIG. 1, rear wall 34 has a doublewall construction andincludes an inner panel 48 and a spaced outer panel 50 that togetherdefine an intake duct 52 within rear wall 34. Intake duct 52 extendsbetween opposite end walls 36 and 38 from the upper edge of rear panel34 downwardly toward the tub floor 40. Although not shown in thefragmentary view of FIG. 1, front wall 32 also has a similar double wallconstruction, with an intake duct extending between the upper edge offront wall 32 and the tub floor 40.

A second subfloor panel 54 is spaced below subfloor panel 44 ingenerally parallel relation to the tub floor 40 and extends between thebottom edges of front wall 32 and rear wall 34 to define an intakechamber 56 beneath subfloor panel 44. The intake chamber 56 togetherwith the induct ducts 52 define a continuous U-shaped intake passagewhich extends downwardly from the upper edge of rear panel 34 betweeninner panel 48 and outer panel 50, forwardly between the subfloor panels44 and 54, and upwardly between the spaced inner and outer panels offront wall 32. Intake chamber 56 communicates with the interior of foodwell 30 through a plurality of downwardly angled louvers 58 formed infront wall 32 and rear wall 34.

A feed fan 60 is centrally positioned in the intake chamber 56 andcommunicates with the return duct 42 through an opening 62 formed insubfloor panel 44. As shown in FIGS. 1 and 2, center feed fan 60 is acentrifugal fan driven by an electric motor 64 and is operable to drawair through the louvers 46 in opposite end walls 36 and 38 and throughU-shaped return duct 42 into the intake chamber 56. Angled flowdiverters 66 direct air beneath subfloor panel 44 outwardly towardsintake ducts 52.

A pair of resistive heating elements 68 and 70 are mounted in the intakechamber 56 and are spaced oppositely about centrifugal fan 60. Theheating elements 68 and 70 are arranged cooperatively with the angleflow diverters 66 such that air is forced across the heating elements asit flows through the intake chamber and towards intake ducts 52.Resistive preheating elements 71a and 71b are disposed in the returnduct 42 adjacent the end walls 36 and 38 to begin heating the air drawnform the food well before the air reaches heating elements 68 and 70 tothereby minimize the time required to reach a startup temperature.

The electric motor 64, heating elements 68 and 70, and preheatingelements 71a and 71b are arranged in a control circuit shownschematically at 72 which includes a thermostatic control means 74adapted for selectively energizing and de-energizing the motor and theheating and preheating elements in response to the air temperature inthe food well. A temperature feedback signal is generated by a thermalsensor means 76 immersed in the path of circulated air.

It is believed that operation of the food conditioning chest can be wellunderstood from the above description and may be summarized as follows.Initially, food stuffs to be preserved are placed on the floor 40 of thefood well 30 within the food chest. In order to circulate air about thefood stuff, centrifugal fan 60 is energized as by motor 64 and air isdrawn from within the food well through louvers 46 formed in theopposite end walls 36 and 38. The return air is continuously drawndownwardly through the upstanding legs of return duct 42 and across thepreheating elements 71a and 71b which are energized in response to atemperature feedback signal from sensor means 76.

Preheated return air flows along the underside of tub floor 40, where itis subsequently drawn through the central opening 62 in subfloor panel44 and introduced into the underlying intake chamber 56. Fan 60 directsa flow of air against the angled flow diverters 66 and across theresistive heating elements 68 and 70 towards intake duct 52. Because theair is preheated within the return duct 42, conductive losses areminimized as the air moves across the heating elements 68 and 70 which,as a direct result thereof, operate at increased efficiency.

Heated intake air then rises upwardly through the intake duct 52 underthe combined influence of gravity and the centrifugal fan 60 and entersthe food well 30 through the angled louvers 58 formed along the upperperiphery of front wall 32 and rear wall 34. Because the louvers 58 areangled downwardly, heated intake air is directed towards the tub floor40 to foodstuffs supported at the bottom of the food well are directlyexposed to the flow of intake air. The streams of heated air from theopposite walls 32, 34 collide and resultingly bend downwardly tocompletely flood the well 30 from top to bottom with the conditionedair, which then flows laterally back into the return duct 42. Thermalenergy is transferred from the intake air to the foodstuffs to warm thefoodstuffs, and the cooled intake air is subsequently evacuated from thefood well through the end walls 36 and 38.

The above-described invention provides a new and improved apparatus forachieving an efficient circulation of conditioned air about foodstuffsstored within a food well. Because the return flow and intake flowcommunicate with the interior of the food well through louvers formed inseparate tub walls, the flows do not oppose each other and insteadfreely circulate about the food well in a substantially unobstructedmanner. Further, because the preconditioned return air flows alongdifferent faces of the food well than the heated conditioned air,conductive losses between the return flow and intake flow are reducedand heat is more efficiently transferred with the interior of the foodwell.

It should be understood that the inventive system is usable in the samemanner for heating and cooling of the well 30.

What is claimed is:
 1. A food conditioning chest for subjectingfoodstuffs contained therewithin to a continuous circulation ofconditioned air, the food conditioning chest comprising:an outer housinghaving an open top; an upwardly opening tub supported in the housing anddefining a food well communicating with the open housing top, the tubhaving at least two pairs of spaced, facing sidewalls cooperativelybounding one of a square and a rectangular space, the sidewallsconnected by a tub floor extending below the open housing top andadapted to support foodstuffs within the food well; air circulationmeans including at least one fan for drawing return air from the foodwell through each of the walls of one of the sidewall pairs and forsupplying intake air to the food well through each of the walls of theother sidewall pair in a continuous flow path; and air conditioningmeans disposed in the continuous flow path for conditioning aircirculated therealong, said air circulation means including a pluralityof groups of louvers in each of the walls of the other of the widewallpairs for directing intake air angularly downwardly and toward the otherof the walls of the other of the sidewall pairs, there being one saidgroup of louvers on each wall of the other wall pair locatedequidistantly from each of the walls in the one wall pair so that airsupplied from each of the walls of the other wall pair midway betweenthe walls in the one wall pair tends to be drawn towards each of thewalls in the one wall pair to avoid the creation of a space midwaybetween the first and second wall pair without air flow.
 2. The foodconditioning chest of claim 1 in which the air circulation meansincludes first duct means for transporting return air from the food wellto the air conditioning means and second duct means for transportingintake air from the air conditioning means to the food well.
 3. The foodconditioning chest of claim 2 in which the air circulation meanscomprises means for supplying intake air solely through both of thewalls of the other of the sidewall pairs.
 4. The food conditioning chestof claim 2 in which the air circulation means comprises means forsupplying return air solely through both of the walls of the one of thesidewall pairs.
 5. The food conditioning chest of claim 4 in which theair circulation means includes a plurality of louvers formed in each ofthe walls of the one sidewall pair approximately midway between each ofthe walls of the other sidewall pair.
 6. The food conditioning chest ofclaim 2 in which the air circulation means comprises diverter meansdisposed in the continuous flow path for diverting return air from atleast one of the walls of the one sidewall pair toward at least one ofthe walls of the other sidewall pair.
 7. The food conditioning chest ofclaim 2 in which the air circulation means includes an intake ductextending downwardly along the at least one of the front wall and fearwall.
 8. The food conditioning chest of claim 1 in which the airconditioning means disposed in the continuous flow path includes atleast one air heating element.
 9. The food conditioning chest of claim 1in which the at least one fan is located substantially midway betweenthe walls in each of the sidewall pairs.
 10. The food conditioning chestof claim 6 in which the fan means comprises a centrifugal fan dependingcentrally from the tub for circulating air in the food well.
 11. Thefood conditioning chest of claim 1 in which the air circulation meanscomprises means for supplying intake air solely through both of thewalls of the other of the sidewall pairs and means for supplying returnair solely through both of the walls of the one of the sidewall pairs.12. The food conditioning chest of claim 1 including means forpreheating return air flowing from the wall towards the air conditioningmeans.
 13. A food conditioning chest for subjecting foodstuffs supportedtherewithin to a continuous circulation of conditioned air, the foodconditioning chest comprising:a housing; a tub on the housing defining aspace for reception of foodstuffs to be subjected to conditioned air inthe food conditioning chest, said space being bounded by a spaced frontand rear wall pair, a spaced end wall pair and a floor, said front andrear wall pair and end wall pair cooperatively bounding one of arectangular and square space; and air circulation means including fanmeans for drawing return air from the tub space through louvers formedin each of the walls in one of the front and rear and end wall pairs andfor supplying intake air to the tub space through louvers formed in eachof the walls in the other of the front and rear and end wall pairs, saidair circulation means including a plurality of groups of louvers in eachof the walls of the other of the wall pairs for directing intake airangularly downwardly and toward the other of the walls of the other ofthe wall parts, there being one said group of louvers on each wall ofthe other wall pair located equidistantly from each of the walls in theone wall pair so that air supplied from each of the walls of the otherwall pair midway between the walls in the one wall pair tends to bedrawn towards each of the walls in the one wall pair to avoid thecreation of a space midway between the first and second wall pairwithout air flow.
 14. The food conditioning chest of claim 13 in whichthe air circulation means includes a return duct extending along the endwalls for transporting return air from the food well to the airconditioning means, said air conditioning means including first andsecond means for separately conditioning air directed through thelouvers in each of the other of the front and rear walls and end walls.15. The food conditioning chest of claim 14 in which louvers are formedin each of the end walls, the return duct extending downwardly alongeach of the end walls and beneath the tub floor and there is apreconditioning means in the part of the air moving between the louversin at least one of the end walls and the fan means.
 16. The foodconditioning chest of claim 14 in which louvers are formed in each ofthe front wall and the rear wall, the intake duct extending downwardlyalong each of the front wall and the rear wall.
 17. The foodconditioning chest of claim 16 in which the intake duct communicateswith an intake passage formed beneath the return duct.